Product details:

Its fully taped, 3-layer Gore-Tex Pro shell ensures waterproof protection and breathable performance, yet the jacket itself manages to weighs in under a pound. Arc'teryx also designed the Alpha AR with WaterTight underarm zippers for ventilation and a helmet-compatible StormHood for secure coverage from bad weather. An athletic fit makes the Alpha AR Jacket slim for bulk-free comfort, and an e3D design ensures a full range of motion, yet ensures that the jacket stays in place.